It's a very difficult one. To get anything like a straight answer is probably going to involve hiring a very expensive accountant, and that would just get you an opinion.
Don't forget that we are a small group. The vast majority of retail clients who use derivatives spreadbet. That just leaves institutional traders, or the very few retail clients whom HMRC counts as professional traders and allows to use income tax, where there is none of the matching issues.
Here is the law
(http://www.legislation.gov.uk/ukpga/1992/12/part/IV/enacted)
Sections 143 onwards deal with options and futures. There is nothing there that answers your question.
Logically if you have been submitting tax returns on this basis for the last couple of years, then what you're doing is 'correct', since HMRC has accepted your calculation.
I would imagine HMRC would have no motivation to challenge you unless (a) the amounts of money involved are significant and (b) you're doing something weird, rather than one of a few possible common sense approches or (c) you've changed your approach multiple times to save on tax.
Don't forget that we are a small group. The vast majority of retail clients who use derivatives spreadbet. That just leaves institutional traders, or the very few retail clients whom HMRC counts as professional traders and allows to use income tax, where there is none of the matching issues.
Here is the law
(http://www.legislation.gov.uk/ukpga/1992/12/part/IV/enacted)
Sections 143 onwards deal with options and futures. There is nothing there that answers your question.
Logically if you have been submitting tax returns on this basis for the last couple of years, then what you're doing is 'correct', since HMRC has accepted your calculation.
I would imagine HMRC would have no motivation to challenge you unless (a) the amounts of money involved are significant and (b) you're doing something weird, rather than one of a few possible common sense approches or (c) you've changed your approach multiple times to save on tax.
Hopefully this thread has not gone too cold yet, as this is an interesting discussion, and one of the only places I've managed to find any information on this particular subject! (at least from a UK perspective).
I've been using IB to trade US listed options for the last couple of years, working out the tax calculations/payments in the same way as described by "globaltrader", i.e. as CGT based on the profit/loss of any transactions (converted into GBP on date of transaction minus any charges/commission). I use a spreadsheet to help create a list of all the transactions, which I then plug into http://cgtcalculator.com/ to do the actual tax calculation, and use the output from this on my tax return.
My question is more about the actual matching of the trades, as up to now, I've been using the "name" of each specific option, e.g. "AAPL-17JAN15-100-C" (Apple call option with $100 strike expiring Jan15) so that trades of that same option get matched with each other to calculate the profit/loss, but trades of a different option (for the same underlying stock) would be treated/matched separately. Is this the correct way of doing this, or should different options of the same underlying stock (plus any trades in the actual stock itself) somehow by lumped together and treated as trades in a single entity? Clearly that would be a pretty complicated calculation to try and work out, especially if you have multiple trades of multiple different options, but I'm curious as to how HMRC might see this, and indeed whether anyone has been challenged for doing it the way described above (or any other "sensible" way that they thought was acceptable based on the limited information published about this!).